Installing Microsoft Office 2003 error

Hey everyone,
I'm having trouble with the installation of Microsoft Office 2003 on my PC. I'm currently using Windows 7, and since I've switched to that I am not able to complete the setup. The process is interrupted by the following message:
Error:
“Error 1404. Setup cannot delete the registry keysoftwareclasses.tif. Verify that you have sufficient permissions to access the registry or contact you Information Technology department for assistance."

Please get back to me with any solution you can think of.
Thanks.
